SIP to SIP Calls Do Not Play Ring Ringback Tone

In high load situations, the playback of ringtone for many calls might over utilize the CPU processing of the gateway.

Recommended Action

In this case, it is necessary to use load balancing or configure the gateways to optimally distribute media termination of calls.

The following are some facts regarding ringtone:

Local ringback in SIP is performed with a 180 response process before the call is established.

After the call has been established, ringtone is played back to the caller using an intermediate transfer mechanism. This is accomplished by a transfer to a ringtone playback voip dialpeer on the Gateway. Once the agent answers the call, the caller is then reinvited to the agent. At that point, the ringtone dialog is dropped.

Troubleshooting ringtone issues consists of configuring the dial-peer to match an incoming voip call to the dialed number (DN) that is configured in the SIP Service for Ringtone. For additional information for SIP configuration, refer to the Configuration and Administration Guide for Cisco Unified Customer Voice Portal Guide.

Ringtone playback is not the same as music on hold (MOH) on the Unified CM. For example, when a caller is put on hold at Unified CM phone they hear music. The ringtone playback is separate from this feature.

Necessary items for ringtone playback:Ringback.wav on the Gateway.

Ringtone service and TCL configured on the Gateway.
Dial-peer associated with ringtone service.
Static routes to route calls from Unified CVP to the Gateway.